Gideon Schaller

Indexing XML data stored in a relational database

As XML usage grows for both data-centric and document-centric applications, introducing native support for XML data in relational databases brings significant benefits. It provides a more mature platform for the XML data model and serves as the basis for interoperability between relational and XML data. Whereas query processing on XML data shredded into one or more relational tables is well understood, it provides limited support for the XML data model. XML data can be persisted as a byte sequence (BLOB) in columns of tables to support the XML model more faithfully. This introduces new challenges for query processing such as the ability to index the XML blob for good query performance. This paper reports novel techniques for indexing XML data in the upcoming version of Microsoft® SQL ServerTM, and how it ties into the relational framework for query processing.

Hosting the .NET Runtime in Microsoft SQL server

The integration of the .NET Common Language Runtime (CLR) inside the SQL Server DBMS enables database programmers to write business logic in the form of functions, stored procedures, triggers, data types, and aggregates using modern programming languages such as C#, Visual Basic, C++, COBOL, and J++. This paper presents three main aspects of this work. First, it describes the architecture of the integration of the CLR inside the SQL Server database process to provide a safe, scalable, secure, and efficient environment to run user code. Second, it describes our approach to defining and enforcing extensibility contracts to allow a tight integration of types, aggregates, functions, triggers, and procedures written in modern languages with the DBMS. Finally, it presents initial performance results showing the efficiency of user-defined types and functions relative to equivalent native DBMS features.

Optimizing runtime XML processing in relational databases

XML processing performance in database systems depends on static optimizations such as XML query rewrites, cost-based optimizations such as choosing appropriate XML indices, and the efficiency of runtime tasks like XML parsing and serialization. This paper discusses some of the runtime performance aspects of XML processing in relational database systems using Microsoft® SQL ServerTM 2005s approach as an example. It also motivates a non-textual storage as the preferred choice for storing XML natively. A performance evaluation of these techniques shows XML query performance improvements of up to 6 times.